The distribution of the stable isotopes of the elements carbon, hydrogen, and oxygen in fruits, vegetables, and juices made from fruits and vegetables as well as other fruit products is a valuable tool for the verification of their origin and pretreatment.
- Control of regional origin
The claimed origin of food can be verified by using multi-element-isotope analyses of carbon, nitrogen, oxygen, and strontium:
- allocation of asparagus to defined growing area
- allocation of apples to defined growing area
- Proof of sugar addition in juices from citrus fruits, apple, and pineapples
The determination of carbon isotopes allows the verification of:
- the addition of C4 sugar (e.g. cane sugar)
- the addition of C3 sugar (e.g. beet sugar)
Watering of juices can be recognized by the oxygen and hydrogen isotope signatures. This way a differentation between a organic juice and a re-watered juice from concentrate is possible.
Additional acidification is detectable by analysing carbon isotopes:
- addition of citric acid to juices from citrus fruits, pineapple, and currants
- addition of L-apple acid to juices from apples and saur cherry
- addition of L-ascorbin acid to juices from citrus fruits, pineapple, and currants